Anion Exchange Membrane Fabrication Without Post-Formation Wet Processing
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Solution Overview
Problem
The existing methods for fabricating anion exchange membranes are cumbersome, requiring multiple wet-process steps and the use of organic solvents, which complicates the process and solvent recycling.
Innovation Solution
A method is developed to convert a neutral precursor polymer into a cationic polymer prior to membrane formation, eliminating the need for post-formation wet processing steps and simplifying solvent management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the neutral precursor polymer is converted to cationic polymer after membrane formation, then the anion exchange membrane can be formed, but multiple wet-process steps are required which complicates the process and solvent recycling
Solution Approach 1:
The patent applies preliminary action by converting the neutral precursor polymer to cationic polymer BEFORE membrane formation, rather than after. The cationic polymer is prepared in advance as a dispersion, which is then coated and dried to form the membrane. This eliminates the need for post-formation wet processing steps and ion exchange operations, significantly simplifying the overall process and improving solvent recycling.
2Reliability
If the neutral precursor polymer is converted to cationic polymer after membrane formation, then the anion exchange functionality is achieved, but multiple wet-process steps are required which increases time and resource consumption
Solution Approach 1:
The cationic polymer with anion exchange functionality is prepared in advance as a dispersion, eliminating the need for time-consuming post-formation wet processing steps. The conversion to cationic form occurs before membrane fabrication, so the membrane is ready for use immediately after drying, significantly reducing process time.
3Shape
If the neutral precursor polymer is converted to cationic polymer after membrane formation, then the membrane structure is established, but solvent handling and recycling becomes more complex
Solution Approach 1:
The cationic polymer is prepared as a dispersion in a suitable solvent before membrane formation. This allows the solvent to be managed and recycled during the coating and drying stages, rather than requiring complex solvent handling after membrane formation. The solvent is evaporated during the drying step to form the final membrane, simplifying recovery and recycling processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach streamlines the membrane production process, reduces the complexity of solvent handling, and enhances the ease of solvent recycling, while maintaining the functional integrity of the anion exchange membrane.
Implementation Method 1
reacting the repeat units of Formula (II) in the precursor copolymer with an amine compound comprising a tertiary amino group to form the cationic polymer having a plurality of cationic repeat units of Formula (III)
Implementation Method 2
drying the coating layer to form the anion exchange membrane comprising the cationic polymer
Data Source
AI summary
A method for making an anion exchange membrane is provided. A neutral precursor polymer that contains pendant groups that contain a leaving group is converted to a cationic polymer prior to forming the membrane. The cationic polymer contains pendant groups with a quaternary amino group. This method eliminates the need for multiple wet process steps on the membrane after its formation. Further, this method can improve the ease of solvent capture and recycling compared to previous synthesis methods because these steps occur prior to membrane formation.